C语言字符串两两组合：将长度148的字符串转换为新的字符串

char msg = "abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&()", *buff = malloc(75 * sizeof(char));

for(int i = 0; i < 74; i++) { buff[i] = msg[i*2]; }

buff[74] = '\0';

free(buff);