Language: C

#include<stdio.h>
#include<string.h>

int a[1005],b[1005];

int reverse(int *a,int l,int r)
{
	int i,t;
	for(i=l;i<=r/2;i++)
	{
		t=a[i];
		a[i]=a[l+r-i];
		a[l+r-i]=t;
	}
	return 0;
}

int main()
{
	int n,i,la,lb,lmax,c,tmp;
	char t;
	
	scanf("%d%*c",&n);		//霎灘?扈?焚?悟帥謗牙屓霓ヲ隨ヲ
	
	while(n--)		//隶。邂?	{
		la=0;		//貂?峺
		lb=0;
		c=0;
		memset(a,0,sizeof(a));
		memset(b,0,sizeof(b));
		
		while(1)	//蟄伜?謨ー蟄?		{
			t=getchar();
			if(t>='0'&&t<='9')
			{
				a[la]=t-'0';
				la++;
			}
			else if(t=='\n')
			{
				break;
			}
		}
		
		while(1)
		{
			t=getchar();
			if(t>='0'&&t<='9')
			{
				b[lb]=t-'0';
				lb++;
			}
			else if(t=='\n')
			{
				break;
			}
		}
		
		if(la>80||lb>80)		//霎灘?貅「蜃コ蛻、譁ュ
		{
			printf("overflow\n");
			return 0;
		}

		reverse(a,0,la-1);		//蜿榊髄
		reverse(b,0,lb-1);

		lmax=(la>lb)?la:lb;
		for(i=0;i<=lmax;i++)	//螟ァ謨ー蜉?ウ?		{
			tmp=a[i];
			a[i]=(tmp+b[i]+c)%10;
			c=(tmp+b[i]+c)/10;
		}

		for(i=lmax;i>=0;i--)	//霎灘?
		{
			if(a[i]!=0)
			{
				tmp=i;
				break;
			}
		}

		if(lmax+1>80)			//霎灘?貅「蜃コ蛻、譁ュ
		{
			printf("overflow\n");
			return 0;
		}

		for(i=tmp;i>=0;i--)
		{
			printf("%d",a[i]);
		}
		printf("\n");
	}
	return 0;
}

Compiler output:
main.c: In function 'main':
main.c:41:33: error: break statement not within loop or switch
   41 |                                 break;
      |                                 ^~~~~
main.c: At top level:
main.c:45:17: error: expected identifier or '(' before 'while'
   45 |                 while(1)
      |                 ^~~~~
main.c:59:17: error: expected identifier or '(' before 'if'
   59 |                 if(la>80||lb>80)                //霎灘?貅「蜃コ蛻、譁ュ
      |                 ^~
main.c:65:27: error: expected ')' before numeric constant
   65 |                 reverse(a,0,la-1);              //蜿榊髄
      |                           ^
      |                           )
main.c:66:27: error: expected ')' before numeric constant
   66 |                 reverse(b,0,lb-1);
      |                           ^
      |                           )
main.c:68:17: warning: data definition has no type or storage class
   68 |                 lmax=(la>lb)?la:lb;
      |                 ^~~~
main.c:68:17: error: type defaults to 'int' in declaration of 'lmax' [-Wimplicit-int]
main.c:68:23: error: 'la' undeclared here (not in a function); did you mean 'a'?
   68 |                 lmax=(la>lb)?la:lb;
      |                       ^~
      |                       a
main.c:68:26: error: 'lb' undeclared here (not in a function); did you mean 'b'?
   68 |                 lmax=(la>lb)?la:lb;
      |                          ^~
      |                          b
main.c:69:17: error: expected identifier or '(' before 'for'
   69 |                 for(i=0;i<=lmax;i++)    //螟ァ謨ー蜉?ウ?                {
      |                 ^~~
main.c:69:26: error: expected '=', ',', ';', 'asm' or '__attribute__' before '<=' token
   69 |                 for(i=0;i<=lmax;i++)    //螟ァ謨ー蜉?ウ?                {
      |                          ^~
main.c:69:34: error: expected '=', ',', ';', 'asm' or '__attribute__' before '++' token
   69 |                 for(i=0;i<=lmax;i++)    //螟ァ謨ー蜉?ウ?                {
      |                                  ^~
main.c:71:27: error: 'i' undeclared here (not in a function)
   71 |                         a[i]=(tmp+b[i]+c)%10;
      |                           ^
main.c:71:25: warning: data definition has no type or storage class
   71 |                         a[i]=(tmp+b[i]+c)%10;
      |                         ^
main.c:71:25: error: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
main.c:71:31: error: 'tmp' undeclared here (not in a function)
   71 |                         a[i]=(tmp+b[i]+c)%10;
      |                               ^~~
main.c:71:40: error: 'c' undeclared here (not in a function)
   71 |                         a[i]=(tmp+b[i]+c)%10;
      |                                        ^
main.c:72:25: warning: data definition has no type or storage class
   72 |                         c=(tmp+b[i]+c)/10;
      |                         ^
main.c:72:25: error: type defaults to 'int' in declaration of 'c' [-Wimplicit-int]
main.c:73:17: error: expected identifier or '(' before '}' token
   73 |                 }
      |                 ^
main.c:75:17: error: expected identifier or '(' before 'for'
   75 |                 for(i=lmax;i>=0;i--)    //霎灘?
      |                 ^~~
main.c:75:29: error: expected '=', ',', ';', 'asm' or '__attribute__' before '>=' token
   75 |                 for(i=lmax;i>=0;i--)    //霎灘?
      |                             ^~
main.c:75:34: error: expected '=', ',', ';', 'asm' or '__attribute__' before '--' token
   75 |                 for(i=lmax;i>=0;i--)    //霎灘?
      |                                  ^~
main.c:84:17: error: expected identifier or '(' before 'if'
   84 |                 if(lmax+1>80)                   //霎灘?貅「蜃コ蛻、譁ュ
      |                 ^~
main.c:90:17: error: expected identifier or '(' before 'for'
   90 |                 for(i=tmp;i>=0;i--)
      |                 ^~~
main.c:90:28: error: expected '=', ',', ';', 'asm' or '__attribute__' before '>=' token
   90 |                 for(i=tmp;i>=0;i--)
      |                            ^~
main.c:90:33: error: expected '=', ',', ';', 'asm' or '__attribute__' before '--' token
   90 |                 for(i=tmp;i>=0;i--)
      |                                 ^~
main.c:94:24: error: expected declaration specifiers or '...' before string constant
   94 |                 printf("\n");
      |                        ^~~~
main.c:95:9: error: expected identifier or '(' before '}' token
   95 |         }
      |         ^
main.c:96:9: error: expected identifier or '(' before 'return'
   96 |         return 0;
      |         ^~~~~~
main.c:97:1: error: expected identifier or '(' before '}' token
   97 | }
      | ^