Language: C

i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}

Compiler output:
main.c:1:1: warning: data definition has no type or storage class
    1 | i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}
      | ^
main.c:1:1: error: type defaults to 'int' in declaration of 'i' [-Wimplicit-int]
main.c:1:3: error: type defaults to 'int' in declaration of 'z' [-Wimplicit-int]
    1 | i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}
      |   ^
main.c:1:9: error: type defaults to 'int' in declaration of 't' [-Wimplicit-int]
    1 | i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}
      |         ^
main.c:1:9: error: variably modified 't' at file scope
main.c:1:16: error: return type defaults to 'int' [-Wimplicit-int]
    1 | i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}
      |                ^~~~
main.c: In function 'main':
main.c:1:16: error: type of 'i' defaults to 'int' [-Wimplicit-int]
main.c:1:16: error: type of 'j' defaults to 'int' [-Wimplicit-int]
main.c:1:16: error: type of 'k' defaults to 'int' [-Wimplicit-int]
main.c:1:16: error: type of 'l' defaults to 'int' [-Wimplicit-int]
main.c:1:16: error: type of 'x' defaults to 'int' [-Wimplicit-int]
main.c:1:142: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    1 | i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}
      |                                                                                                                                              ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}
main.c:1:142: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    1 | i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}
      |                                                                                                                                              ^~~~~
main.c:1:142: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:1:159: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    1 | i,z=256,t[z*z];main(i,j,k,l,x){for(;i<z;i++)for(j=i;j<z;j++)for(k=j;k<z;k++)for(l=k;l<z;l++){if((x=i*i+j*j+k*k+l*l)>=z*z)break;t[x]++;}while(scanf("%d",&x),x)printf("%d\n",t[x]);return 0;}
      |                                                                                                                                                               ^~~~~~
main.c:1:159: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:159: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:1:159: note: include '<stdio.h>' or provide a declaration of 'printf'