NSString *testA = @"123";

NSString *testB = @"789";

????1. 字符串拼接

NSString *testString = [NSString stringWithFormat:@"%@%@",testA, testB];

? ? 2.?字符轉(zhuǎn)NSInteger

NSInteger testC = [testString integerValue];

? ? 3.?NSInteger轉(zhuǎn)字符

NSString *testD = [NSString stringWithFormat:@"%ld", testC];

? ? 4.?字符轉(zhuǎn)int

int intString = [testString intValue];

? ? 5.?int轉(zhuǎn)字符

NSString *stringInt = [NSString stringWithFormat:@"%d", intString];