53. strripos
54. strrpos
55. strspn
56. strstr
57. strtok
58. strtolower
59. strtoupper
60. strtr
61. substr_compare
62. substr_count
63. substr_replace
64. substr
65. trim
66. ucfirst
67. ucwords
68. vprintf
//69. vsprintf
70. wordwrap