strToInt

测试:

struct TestInput{    const char* str;    int expectedRetValue;    int expectedErrStatus;} ;TestInput inputs[] ={    {"123", 123, kValid},    {"+123", 123, kValid},    {"-123", -123, kValid},    {" 123", 123, kValid},    {"123abc", 123, kValid},    {"123.", 123, kValid},    {NULL, 0, kInvalid},    {"", 0, kInvalid},    {"+", 0, kInvalid},    {"-", 0, kInvalid},    {".123", 0, kInvalid},    {"abc", 0, kInvalid}};#include <cstdio>#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))void testStrToInt(){    int failed = 0;    unsigned int i = 0;    for (i=0; i<ARRAY_SIZE(inputs); ++i)    {        int ret = 0;        if ((inputs[i].expectedRetValue != (ret=strToInt(inputs[i].str)))                || (inputs[i].expectedErrStatus != g_error_status))        {            ++failed;            printf("\ncase %d failed\n"                   "input %s\n"                   "expected:ret=%d,err=%d\n"                   "actual:ret=%d,err=%d\n",                   i,                   inputs[i].str,                   inputs[i].expectedRetValue, inputs[i].expectedErrStatus,                   ret, g_error_status);        }    }    printf("\ntest done! total %d cases, %d ok, %d failed\n",           i, i-failed, failed);}

实现：

#define NULL 0typedef enum{    kValid,    kInvalid} ErrorStatus;ErrorStatus g_error_status = kInvalid;static bool isDigit(char c){    return !((c-'0') < 0 || (c-'0') >9);}static bool isWhiteSpace(char c){    return ((c == '\t') || (c == ' '));}static bool overflowForIntType(bool minus, long long num){    return ( (minus && num < (signed int)0x80000000)             || (!minus && num > 0x7fffffffL));}static const char* ignoreWhitespace(const char* str){    while(*str && isWhiteSpace(*str))    {        str++;    }    return str;}/*should pass below test cases:|----------------------------|input|return|g_error_status|----------------------------|123|123|kValid|----------------------------|+123|123|kValid|----------------------------|-123|-123|kValid|----------------------------|[blank]123|123|kValid|----------------------------|[tab]123|123|kValid|----------------------------|123abc|123|kValid|----------------------------|123.|123|kValid|----------------------------|[null]|0|kInvalid|----------------------------|""|0|kInvalid|----------------------------|+|0|kInvalid|----------------------------|-|0|kInvalid|----------------------------|.123|0|kInvalid|----------------------------|abc|0|kInvalid|----------------------------*/int strToInt(const char* str){    g_error_status = kInvalid;    if ( (NULL == str) || (*str == '\0'))    {        return 0;    }        const char* cur = ignoreWhitespace(str);    bool minus = false;    if (*cur == '-')    {        minus = true;        ++cur;    }    else if (*cur == '+')    {        ++cur;    }        long long result = 0;    bool isNum = false;    while((*cur != '\0'))    {        if (!isDigit(*cur))        {            break;        }        else        {            isNum = true;            result = result*10 + (*cur - '0') ;        }        cur++;    }        if (!isNum)    {        return 0;    }            if (minus)    {        result = -1*result;    }    if (overflowForIntType(minus, result))    {        return 0;    }        g_error_status = kValid;    return (int)result;}