string源代码.docx

String类源代码一.C字符串1. strlen(),计算字符串长度int strlen(const char string) { int i=0; while(string[i]) i++; return i; }2. strcpy(), 字符串拷贝. char *strcpy(char *destination, const char *source) { while(*destinaton++=*source++); return (destination-1); }3. strcat(), 字符串的连接. char *strcat(char *target,const char *source) { char *original=target; while(*target) target++; // Find the end of the string while(*target++=*source++); return(original); }4. streql(), 判断两个字符串是否相等. int streql(char *str1,char *str2) { while((*str1==*str2)(*str1)) { str1++; str2++; } return((*str1==NULL)(*str2==NULL)); }5. strchr(), 在字符串中查找某个字符. char *strchr(const char *string,int letter) { while((*string!=letter)(*string)) string++; return (string); }6. chrcnt(), 计算某个字符在字符串中出现的次数. int chrcnt(const char *string,int letter) { int count=0; while(*string) if(*string==letter)count++; return count; }7. strcmp(), 判断两个字符串是否相等. int strcmp(const char *str1,const char *str2) { while((*str1==*str2)(*str1)) { str1++; str2++; } if((*str1==*str2)(!*str1)) //Same strings return o; else if((*str1)(!*str2)) //Same but str1 longer return -1; else if((*str2)(!*str1)) //Same but str2 longer else return((*str1*str2)?-1:1); }二. String类1．int size(string str){//return the size of a stringint count = 0;while(str[count]){count++;}return count;}2． bool empty(string str){//check whether a string is empty or notbool empty = false;if(size(str) == 0){empty = true;}return empty;}3． int find1(string str, char a, int index){//return the index of a specific character begin from the start index//如果index =0，直接初始化i = 0int i = index;while(i str.size()){if(str[i] == a){break;}i++;}return i;}4． int find2(string str, char a, int index){//从index起倒着数找a//如果无index，直接初始i = str.size() - 1int i = index;while(i = 0){if(str[i] == a){break;}i--;}return i;}5． int find3(string str, string aa){//查一个string, 返回index//若有startindex，则初始化i = startindexint index;for(int i = 0; i str.size(); i++){if(str[i] == aa[0]){int m = i;int n = 0;bool check = true;for(/*int m =